An existing multilayer inductor is described in, for example, Japanese Unexamined Patent Application Publication No. 2008-130970 (Patent Document 1). The multilayer inductor according to Patent Document 1 is described below with reference to the accompanying drawings. FIG. 4 is an exploded perspective view of a multilayer body 111 of the multilayer inductor described in Patent Document 1.
The multilayer body 111 includes magnetic layers 112a to 112l, internal conductors 114a to 114f, and via hole conductors B1 to B5. The magnetic layers 112a to 112l are insulating layers arranged from top to bottom in this order in the stacking direction.
The internal conductor 114a is disposed on the magnetic layer 112d. One end of the internal conductor 114a is led out and exposed through the right side surface of the multilayer body 111. The internal conductors 114b to 114e loop through a length of one turn on the magnetic layers 112e to 112h, respectively. One end of each of the internal conductors 114b to 114e has a corresponding one of connection portions 116b to 116e. The internal conductors 114b and 114d have the same shape. The internal conductors 114c and 114e have the same shape. In addition, the internal conductor 114f is disposed on the magnetic layer 112i, and one end of the internal conductor 114f is led out and exposed through the left side surface of the multilayer body 111.
Furthermore, the via hole conductors B1 to B5 connect neighboring ones of the internal conductors 114a to 114f in the stacking direction to each other. Thus, a coil L having a spiral shape is formed in the multilayer body 111.
Note that as described in more detail below, the multilayer inductor described in Patent Document 1 has a disadvantage in that delamination easily occurs. FIG. 5 is a see-through plan view of the multilayer body 111 viewed from the top in the stacking direction. In FIG. 5, the internal conductors 114a to 114f overlap one another.
As shown in FIG. 5, the multilayer body 111 has a square region E formed therein and surrounded by the connection portions 116b to 116e and the internal conductors 114a to 114f. In the region E, the internal conductors 114a to 114f are not formed. Accordingly, the thickness of the multilayer body 111 in the region E in the stacking direction is smaller than that in a region in the vicinity of the region E (a region in which the internal conductors 114a to 114f are formed) by the thicknesses of the connection portions 116b to 116e and the thicknesses of the internal conductors 114a to 114f. Accordingly, when the multilayer body 111 is pressure-bonded, a pressing tool cannot enter the region E. Thus, a sufficient pressure may not be applied to the region E. As a result, delamination easily occurs in the region E of the multilayer inductor described in Patent Document 1.